The invention relates to a circular knitting machine for the production of high pile fabrics having combed-in fibres, having a needle cylinder in which knitting needles are displaceably mounted which define a circular knitting field along the upper edge of the needle cylinder, and having a plurality of carding devices disposed along the knitting field and an exhaust means disposed above the knitting field.
In known circular knitting machines of this kind U.S. Pat. No. 3,999,405 dated Dec. 28, 1976, four to sixteen carding devices, as a rule, are disposed along the knitting field, consisting each of at least one feeder feeding a sliver, a carding cylinder, a combing cylinder and an evening or cleaning cylinder, and therefore they conceal the knitting area such that it is scarcely visible from the outside. In addition, the space above the needle cylinder is covered over by the exhaust device, so that the already poor visibility is further impaired by the insufficient entry of light. It is therefore not possible to observe the combing-in process, i.e., the passage of the knitting needles through the wires of the combing-in cylinders and thus the insertion of the fibers into the knitting needles, nor can the knitting process which directly follows the combing-in process be observed. This results in difficulty in the first setting up of the machine and in cases in which changes become necessary or trouble occurs during production.
The convenience of operation of the known circular knitting machines of the kind described in the beginning is furthermore, and aside from the poor lighting and visibility, limited by the fact that, after a carding device has been removed, only the portion of the knitting field opposite the removed carding device is directly visible. Therefore if, for example, too many or too few fibers are being fed at this opposite position, this problem could be seen, and could be eliminated by controlling the fiber feed. If, on the other hand, a needle fault, for example, is involved, which also might be seen when the defective needle moves past the area on the above-mentioned opposite side, the defective needle has to be shifted by turning the needle cylinder step by step to the portion of the knitting field that has been made accessible by the dismounting of the carding device, where the defective needle can be removed or replaced with a new needle. At the same time the difficulty arises that, at the location of the dismounted carding device only the fronts of the needles are visible and therefore the defective needle often cannot be identified at that location.
The greater the number of systems and hence carding devices that are provided on the circular knitting machine, the greater are the problems which have been described.